Foucart (1875) and Ortner (1899) were the first to describe unilateral pulmonary edema as a complication of drainage of hydrothorax. Although various causes have been reported for this entity, it continues to be rare. We report a case of right unilateral pulmonary edema due to thrombosis of the superior pulmonary vein that was detected while a patient was in the recovery room after bilateral lobectomy for pulmonary tumors. The possible pathophysiological mechanisms contributing to pulmonary edema are discussed.